This invention relates to a hydrophobic coating system including diamond-like carbon (DLC) and at least one fluoro-alkyl silane (FAS) compound provided on (directly or indirectly) a substrate of glass, plastic, ceramic, or the like, and a method of making the same. The coating system may include one or more layers, and the DLC portion of the coating may be deposited on the substrate utilizing plasma ion beam deposition in certain embodiments.
Conventional substrates (e.g., glass) are susceptible to retaining water on their surfaces in many different environments, e.g., when used as automotive windows (e.g. backlites, side windows, and/or windshields) or as architectural/residential windows. When water is retained or collects on automotive windows, the water may freeze (i.e. forming ice). Additionally, the more water retained on a windshield, the higher power wiper motor(s) and/or wiper blade(s) required.
Thus, there exists a need in the art for a coated article (e.g. coated glass, ceramic or plastic substrate) that can repel water and/or dirt, and a method of making the same.
It is known to provide diamond like carbon (DLC) coatings on glass. U.S. Pat. No. 5,637,353, for example, states that DLC may be applied on glass. Unfortunately, the DLC of the ""353 patent would not be an efficient hydrophobic coating.
U.S. Pat. No. 5,250,322 to Takahashi et al., discloses a water-repellant coating including FAS on a glass substrate. Unfortunately, the water-repellant coatings of the ""322 patent may not be durable enough for certain applications (e.g., it may be prone to scratching, breaking down, etc. in automotive and/or other harsh environments).
In view of the above, it is apparent that there further exists a need in the art for a durable protective hydrophobic coating system that is somewhat resistant to scratching, damage, or the like.
It is a purpose of different embodiments of this invention to fulfill any or all of the above described needs in the art, and/or other needs which will become apparent to the skilled artisan once given the following disclosure.
An object of this invention is to provide a durable coated article that can shed or repel water (e.g. automotive windshield, automotive backlite, automotive side window, architectural window, bathroom shower glass, residential window, bathroom shower door, coated ceramic article/tile, etc.).
Another object of this invention is to provide a hydrophobic coating system including one or more diamond-like carbon (DLC) inclusive layers.
Another object of this invention is to provide a hydrophobic coating system including each of DLC and FAS, the DLC being provided for durability purposes and the FAS for increasing the contact angle of the coating system.
Yet another object of this invention, in embodiments where a hydrophobic coating system includes multiple DLC inclusive layers and at least one FAS layer, is to form (e.g., via ion beam deposition techniques) a first underlying DLC inclusive layer using a first precursor or feedstock gas and a second DLC inclusive layer over the first underlying DLC inclusive layer using a second precursor or feedstock gas. The FAS inclusive layer may then be applied over the DLC layers in any suitable manner. In certain embodiments, the first underlying DLC inclusive layer may function as an anchoring and/or barrier layer while the second or overlying DLC inclusive layer may be more scratch resistant (i.e., harder) and/or more dense so as to improve the coated article""s durability and/or scratch resistance.
Another object of this invention is to provide a coated substrate, wherein a coating system includes sp3 carbon-carbon bonds and FAS, and has a wettability W with regard to water of less than or equal to about 23 mN/m, more preferably less than or equal to about 21 mN/m, even more preferably less than or equal to about 20 mN/m, and in most preferred embodiments less than or equal to about 19 mN/meter. This can also be explained or measured in Joules per unit area (mJ/m2)
Another object of this invention is to provide a coated substrate, wherein a coating system includes sp3 carbon-carbon bonds and FAS, the coating system having a surface energy xcex3c (on the surface of the coated article) of less than or equal to about 20.2 mN/m, more preferably less than or equal to about 19.5 mN/m, and most preferably less than or equal to about 18 mN/m.
Another object of this invention is to provide a coated substrate, wherein a DLC and FAS inclusive coating system has an initial (i.e. prior to being exposed to environmental tests, rubbing tests, acid tests, UV tests, or the like) water contact angle xcex8 of at least about 80 degrees, more preferably of at least about 100 degrees, even more preferably of at least about 110 degrees, and most preferably of at least about 125 degrees.
Another object of this invention is to provide a coated glass article wherein a DLC and FAS inclusive coating system protects the glass from acids such as HF, nitric, and sodium hydroxide.
Another object of this invention is to provide a coating system for a substrate that is abrasion resistant.
Another object of this invention is to manufacture a coated article having hydrophobic qualities wherein the temperature of an underlying glass substrate may be less than about 200xc2x0 C., preferably less than about 150xc2x0 C., most preferably less than about 80xc2x0 C., during the deposition of a DLC and FAS inclusive coating system. This reduces graphitization during the deposition process, as well as reduces detempering and/or damage to low-E and/or IR-reflective coatings already on the substrate in certain embodiments.
Yet another object of this invention is to fulfill any and/or all of the aforesaid objects and/or needs.
According to certain exemplary embodiments, this invention fulfills any and/or all of the above described needs and/or objects by providing a coated article comprising:
a substrate;
a hydrophobic coating system provided on said substrate, said hydrophobic coating system including at least one diamond-like carbon (DLC) inclusive layer and at least one fluoro-alkyl silane (FAS) compound inclusive layer; and
wherein said hydrophobic coating system has an initial contact angle xcex8 of at least about 80 degrees, and an average hardness of at least about 10 GPa.
This invention further fulfills any and/or all of the above described objects and/or needs by providing a method of making a coated article, the method comprising the steps of:
providing a substrate;
depositing a first DLC inclusive layer on the substrate using a first gas including silicon (Si);
depositing a second DLC inclusive layer on the substrate over the first DLC inclusive layer using a second gas different than the first gas; and
applying a FAS inclusive layer over said second DLC inclusive layer in a manner such that the resulting article has an initial contact angle xcex8 of at least about 80 degrees.
This invention will now be described with respect to certain embodiments thereof, along with reference to the accompanying illustrations.